JP2007248388A - Instrument for measuring aerosol transmissivity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument for measuring aerosol transmissivity, capable of improving measurement time delays and reducing the size of the overall instrument and having high measurement accuracy. <P>SOLUTION: The aerosol transmissivity measuring instrument is provided with: a light projection and reception part for projecting and receiving light; a reflection part having a first reflecting mirror for reflecting light from the light projection and reception part to the light projection and reception part; a measuring tube integrally provided with the light projection and reception part and the reflecting mirror in corresponding manner; and a means for calibrating absolute values and circulating air into the measuring tube. The intensity of light transmitted through air is measured at normal measuring times and at absolute value measuring times to measure the transmissivity of light. The light projection and reception part has a second reflecting mirror. The second reflecting mirror has a first pinhole for passing light to be projected into the measuring tube and a second pinhole for passing light multiply reflected between the first reflecting mirror and the first reflecting mirror to a light reception part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a haze transmittance measuring apparatus for optically measuring the haze transmittance of polluted air inside a road tunnel or the like.

  Conventionally, this type of haze transmittance measuring device is provided with a light projecting unit and a light receiving unit separated by about 100 m, and the light is transmitted from the light projecting unit into the fumes where soot and dust float, and the transmittance is measured. To do.

  A conventional haze transmittance measuring device is equipped with a calibration function to compensate for a decrease in measured value due to light beam attenuation of a light source of a light projecting unit, aging deterioration of a light receiving unit element, dirt on a lens surface, and the like. Was calibrated to compensate for the decline.

  At that time, since the absolute value (100%) of the light transmittance cannot be created arbitrarily, it can be adjusted by visual observation at the measurement site or by setting the maximum value by recording the setting value. Could increase.

Therefore, for example, a haze transmittance measuring device described in Patent Document 1 has been proposed. (See Patent Document 1).
Japanese Patent No. 3539112

  In the smoke transmittance measuring device described in Patent Document 1, since the light projecting / receiving unit and the reflecting unit are integrally provided via the measurement tube, it is not necessary to perform on-site adjustment such as optical axis alignment, Since the absolute value (100%) of the light transmittance is measured by replacing dirty air and clean air in the measuring cylinder, unlike the case of conventional visual observation, errors can be almost eliminated.

  However, the haze transmittance measuring device described in Patent Document 1 is a closed path method in which the measurement unit is sealed with an outer cylinder (measurement cylinder), and the outer cylinder has a considerable volume in conjunction with the measurement optical path length. Therefore, it may take time to fill the measurement cylinder with the contaminated air sucked by the pump.

  Moreover, since the haze transmittance measuring apparatus described in Patent Document 1 is provided with a reflecting mirror only on one side (reflecting part side), the measuring light can only reciprocate within the measuring cylinder. Normally, the closed-path type haze transmittance measuring device has a limitation on the size of the entire device, and the measurement optical path length obtained by one round trip is shorter than the desired measurement optical path length (for example, 100 m) (for example, for example, 4-5 m). Therefore, there is a method for obtaining the light transmittance obtained from the short measurement optical path length by converting it to the light transmittance of a desired measurement optical path length. However, when this method is used, an error due to the conversion may increase. For example, when a light transmittance with a measurement optical path length of 5 m actually measured is converted into a light transmission with a measurement light path length of 100 m, the light transmittance with a measurement light path length of 5 m is obtained by the 20th power. The effect will not be negligible.

  The present invention has been made in view of the above circumstances, and has improved the measurement time delay, and is capable of obtaining the light transmittance of a desired measurement optical path length with high accuracy while downsizing the entire apparatus. An object is to provide an apparatus.

  The smoke transmittance measuring device of the present invention includes a light projecting / receiving unit that projects and receives light, a reflection unit that includes a first reflecting mirror that reflects light from the light projecting / receiving unit, and the light projecting / receiving unit. A measuring tube provided integrally with the light receiving portion and the reflecting portion, and an absolute value calibration means for circulating air in the measuring tube; and at the time of normal measurement and absolute value measurement in the light projecting / receiving portion. A haze transmittance measuring device that measures the light transmittance by measuring the intensity of light transmitted through the air, wherein the light projecting and receiving unit includes a second reflecting mirror, and the second reflecting mirror Passes the first pinhole that allows the light projected into the measuring tube to pass through, and the light that has been multiple-reflected between the second reflecting mirror and the first reflecting mirror, to the light receiving section. A second pinhole.

  With this configuration, the measurement light can be subjected to multiple reflections between the light projecting / receiving unit and the reflection unit, so that the measurement light can be measured with a desired measurement optical path length. Therefore, since the desired distance of the measurement optical path length can be obtained by the multiple reflection, the measurement cylinder that accommodates the air to be measured can be reduced in size. When the measuring cylinder is reduced in size, the volume of the measuring cylinder is reduced, so that the time required to accommodate air in the measuring cylinder is shortened.

  In addition, the haze transmittance measuring device of the present invention includes a shaft that integrally forms the light projecting / receiving portion and the reflecting portion, and a center of gravity position of a central portion of an optical device portion that is integrally formed by the shaft. And a base portion fixed with a support bracket.

  With this configuration, the light projecting / receiving unit and the reflecting unit are fixed integrally with, for example, an Invar shaft so that the optical axis does not shift, and is resistant to vibrations, and is capable of expanding and contracting the member due to temperature changes. However, it can be stably fixed to the base portion at the center of gravity of the central portion of the optical device portion so as to be stable.

  In the haze transmittance measuring apparatus of the present invention, the first reflecting mirror and the second reflecting mirror are astigmatism mirrors.

  With this configuration, the light beam of the measurement light can be reduced. Therefore, the response time for air contamination can be shortened by further reducing the internal volume of the measuring cylinder and reducing the volume of the contaminated air from the outside.

  In the haze transmittance measuring apparatus of the present invention, an embedding material is formed on the inner wall of the measuring cylinder.

  This configuration eliminates the gap between the inner wall of the measuring tube and the luminous flux with the embedding material, so that the volume of dirty air from the outside can be reduced, and thus the response time to air dirt can be shortened. Can do.

  In the haze transmittance measuring apparatus of the present invention, the light projecting / receiving unit and the measurement tube are joined via a dust-proof tube, and the dust-proof tube has dust-proof glass and is formed on the second reflecting mirror. A light receiving cylinder is provided on the light projecting / receiving part side of the second pinhole, and a light receiving element is provided inside or at the exit of the light receiving cylinder.

  With this configuration, the measurement light finally reaching the second reflecting mirror through multiple reflection enters the light receiving cylinder through the second pinhole and is photoelectrically converted by the light receiving element in the back. Therefore, it is possible to prevent the influence of scattered light due to the dust adhering to the dust-proof glass during light reception, and to calculate the light transmittance and the light absorption coefficient with high accuracy.

  Further, in the haze transmittance measuring apparatus of the present invention, the light projecting / receiving unit and the measurement cylinder are joined via a dust-proof cylinder, the dust-proof cylinder has dust-proof glass, and the measurement cylinder has the dust-proof cylinder A clean air generator is provided that has a blow-out port near the surrounding outer periphery and that sends clean air to the blow-out port.

  Further, in the haze transmittance measuring device of the present invention, the reflecting portion and the measurement tube are joined via a dust-proof tube, the dust-proof tube has dust-proof glass, and the measurement tube surrounds the dust-proof tube. A clean air generating unit that has a blowout port near the outer periphery and sends clean air to the blowout port.

  With this configuration, the clean air sent out from the clean air generating unit flows into the measurement cylinder from the outlet provided on the outer periphery of the dust-proof cylinder. By this air flow, the contaminated air can be prevented from approaching the dust-proof glass provided in the light projecting / receiving part and the reflecting part, and the dust of the contaminated air can be prevented from adhering to the dust-proof glass.

  The dust-proof glass of the haze transmittance measuring device of the present invention is provided inside the dust-proof cylinder.

  With this configuration, adhesion of soot and dust to the dust-proof glass can be suppressed.

  Moreover, as for the haze transmittance measuring apparatus of this invention, the said measurement cylinder has an opening-closing part.

  With this configuration, the open / close portion can be opened after measurement, and the reflector can be easily and regularly cleaned of dirt.

  In addition, the haze transmittance measuring apparatus of the present invention is provided with a calculation means for converting the transmittance obtained from the measured optical path length of the multiple reflected light into the desired measured optical path length.

  With this configuration, since the transmittance of the desired measurement optical path length is obtained by conversion, the number of reciprocations between the light projecting / receiving unit and the reflection unit can be reduced, and the measurement optical path can be shortened by multiple reflection by the projection light. Therefore, it is possible to suppress a decrease in transmitted light due to scattering by dust-proof glass to which dust / dust adheres and irregular reflection by the reflecting mirror. Even in the case of conversion, since a constant measurement optical path length (for example, about 30 to 60 m) can be ensured by multiple reflection, the influence of error due to conversion can be reduced.

  Further, in the haze transmittance measuring apparatus of the present invention, the calculation means performs visibility correction for adapting the transmittance to human visibility characteristics.

  With this configuration, it is possible to measure transmittance suitable for human visibility characteristics.

  Further, in the haze transmittance measuring apparatus of the present invention, the calculation means is after a set time has elapsed since the start of absolute value calibration, and when the measured transmittance value has converged within a set range, The average value of the measured values is an absolute measured value.

  With this configuration, an absolute measurement value with high accuracy can be obtained, and the measurement accuracy of transmittance is improved.

  According to the haze transmittance measuring apparatus of the present invention, it is possible to improve the measurement time delay and obtain the light transmittance of a desired measurement optical path length with high accuracy of transmittance measurement while downsizing the entire apparatus. That is, by performing multiple reflections between the second reflecting mirror and the first reflecting mirror, for example, in order to measure the transmittance when the measurement optical path length is 100 m, the transmission of the conventional one reciprocating short span (4 m to 5 m) is performed. It is not necessary to convert the distance from the rate to 100 m, and the accuracy is greatly improved as compared with the prior art.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a schematic configuration of the haze transmittance measuring apparatus according to the first embodiment. FIG. 2 shows a schematic configuration of the optical device unit and the absolute value calibration unit. FIG. 3A is a front view of a reflecting mirror provided on the light projecting / receiving unit side. As shown in FIG. 1, the haze transmittance measuring device 100 includes an optical device unit 9 that measures the intensity of light by multiple reflection of light projected from a light source, and clean air in the measurement cylinder 3. An absolute value calibration unit 4 that satisfies and calibrates an absolute value and a control unit 5 that calculates a light transmittance or an extinction coefficient are configured.

  The optical device unit 9 includes a light projecting / receiving unit 1 that projects light into the measurement tube 3, a reflection unit 2 that reflects light from the light projecting / receiving unit 1, and a measurement tube 3 into which air to be measured flows. Yes. The light projecting / receiving unit 1 and the reflecting unit 2 are integrally installed by, for example, four Invar shafts 8 so as to face each other via the measuring cylinder 3. The material of the shaft is preferably a material having high durability and a low coefficient of thermal expansion near room temperature.

As shown in FIG. 2, a dust-proof tube 10 is provided between the light projecting / receiving unit 1 and the measurement tube 3, and a dust-proof glass 11a is provided on the exit surface of the dust-proof tube on the measurement tube 3 side. Similarly, a dust-proof tube 10 is provided between the reflecting portion 2 and the measurement tube 3, and a dust-proof glass 11b is provided on the exit surface of the measurement tube 3 side surface of the dust-proof tube.
In addition, in order to suppress the decrease in the smoke transmittance due to dust and dust adhering to the dust-proof glass, the laser light measurement optical path is shortened, the light beam diameter is reduced, the dust-proof cylinder diameter is also reduced, the dust-proof cylinder is lengthened, Glass may be provided inside the dust-proof cylinder.

  The optical device section 9 is supported by a support fitting 6 at the center of gravity, and the support fitting 6 is fixed to the base 7.

  The light projecting / receiving unit 1 has a light source that emits light in a light beam state such as a semiconductor laser / LED, and includes a light projecting unit 13 that projects light into the measuring tube 3 by the light source, and a photoelectric conversion unit / preamplifier circuit. The light-receiving part 14 which receives the light reflected from the part 2 and converts it into an electrical signal, and the reflecting mirror 12a which has the pinhole which lets light pass are provided.

  The reflecting mirror 12a of the first embodiment is a concave mirror, and as shown in FIG. 3A, in the measuring cylinder 3, the pinhole 3a for allowing the light projected from the light projecting unit 13 into the measuring cylinder 3 and the measuring cylinder 3 are passed. And a pinhole 3b through which the light finally reflected toward the light receiving unit 14 through the multiple reflection is passed.

  The positions of the pinholes 3a and 3b can be determined by using a concave mirror reflection calculation method (ABCD matrix). For example, using the coordinate axis of the concave mirror, the initial coordinates (x, y), the distance L of the two concave mirrors, the radius of curvature ρ of the two concave mirrors, and the number of reciprocations m are entered, and the calculation of the concave mirror reflection described above is performed. By this method, the reflection point of the final reflector at the m-th round trip can be obtained as a second pinhole (3b) that allows light to pass to the light receiving part. Further, the position of the initial coordinate is defined as a first pinhole (3a) that projects light.

  FIG. 3B shows the reflection points on the two concave mirrors calculated by the above calculation method. FIG. 3B (a) shows a reflection point on the concave mirror 12a on the light projecting / receiving part side, and FIG. 3B (b) shows a reflection point on the concave mirror 12b on the reflection part side. As shown in FIG. 3B, between the concave mirrors facing each other, the reflection points are continuously located at adjacent positions by repeating the reflection of light, and as a result of multiple reflection, the reflection points are located so as to draw a circle. .

  Here, FIG. 3C shows reflection points on the two astigmatism mirrors when the astigmatism mirror is used as the reflector. FIG. 3C (a) shows a reflection point on the astigmatic mirror 20a on the light projecting / receiving part side, and FIG. 3C (b) shows a reflection point on the concave mirror 20b on the reflection part side. As shown in FIG. 3C, between the astigmatisms facing each other, the reflection point is continuously located at the adjacent position by repeating the reflection, and as a result of the multiple reflection, it is located so as to draw an ellipse where the reflection point intersects. ing.

  The reflecting unit 2 includes a concave mirror 12b similar to the light projecting / receiving unit 1. The reflecting mirror 12a and the reflecting mirror 12b have a radius of curvature ρ as described in the above manufacturing conditions, adjust the projection angles (α, β) of light emitted from the pinhole 3a, and enter the measuring tube 3 Between the reflecting mirrors facing each other, the projected light is reflected back and forth between the reflecting mirrors 12a and 12b m times and has a measurement optical path length of 100 [m] incident on the pinhole 3b. Adjusted and installed.

  The absolute value calibration unit 4 includes an inlet solenoid valve 15 that controls the inflow of contaminated air from a tunnel, a calibration solenoid valve 16 that opens and closes during absolute value calibration, a first filter 17a, and a second filter 17b. And a discharge electromagnetic valve 18 for controlling the discharge of air after the measurement, a suction pump 19, and a hose 50. The hose 50 is preferably a hose that is not easily charged so that dust and soot are less likely to adhere. For example, an antistatic tube in which the tube is made conductive to prevent static electricity and dust.

(Operation during absolute value measurement)
The smoke transmittance measuring apparatus 100 configured as described above opens the calibration electromagnetic valve 16 of the absolute value component 4 and closes the inlet electromagnetic valve 15 and the discharge electromagnetic valve 18 during absolute value measurement. The suction pump 19 circulates the contaminated air in the measurement cylinder 3 so as to pass through the first filter 17 a and the second filter 17 b in the absolute value calibration unit 4.

  By circulating the polluted air so as to pass through the above-described filter, dust and the like are removed from the polluted air, and the air in the measuring tube 3 eventually becomes 100% transmissible. Measurement is performed in a state where the air in the measuring cylinder 3 has a transmittance of 100% and is stored in the control unit 5 as an absolute value.

  The control unit 5 waits from the start of absolute value calibration until a predetermined set time elapses, that is, until the measured value is stabilized, and then when the measured value of transmittance converges within the set range, the set time is reached. An average value of measured values after elapse may be set as an absolute measured value. With this configuration, an absolute measurement value with high accuracy can be obtained, and the measurement accuracy of transmittance is improved.

(Operation during normal measurement)
At the time of normal measurement, the smoke transmittance measuring apparatus 100 first opens the inlet solenoid valve 15 and the discharge solenoid valve 18 of the absolute value calibration unit 4 and closes the calibration solenoid valve 16. Then, the suction pump 19 sucks contaminated air in the tunnel or the like into the measuring cylinder 3.

  Next, as shown in FIG. 4A, the light is transmitted from the light projecting unit 13 of the light projecting / receiving unit 1 toward the measuring tube 3 so as to pass through the pinhole 3a of the reflecting mirror 12a installed in the light projecting / receiving unit 1. Project. The projected measurement light reaches the reflecting mirror 12b of the reflecting section 2 through the measuring tube 3 in which dust and soot float. This light is reflected toward the light projecting / receiving unit 1. The reflected light again passes through the measuring tube 3 and reaches the reflecting mirror 12a in the light projecting / receiving unit 1 and is reflected again to the reflecting unit 2 side.

  The multiple reflected light finally reaches the pinhole 3b of the reflecting mirror 12a in the light projecting / receiving unit 1 and passes therethrough. The passed light is converted into an electric signal by the photoelectric conversion unit in the light receiving unit 14 and transmitted to the control unit 5.

In the control unit 5, the light transmittance or the extinction coefficient is calculated based on the electric signal (voltage). That is, generally, the light transmittance _TL of the haze particle layer or the like is expressed by the following equation (1).

Since the value of the electric signal includes noise and temperature drift, it is necessary to remove them. For this reason, the light transmittance T _L1 from which the error is removed using an electrical signal for blocking the measurement light (0% calibration) is obtained by the following equation.

Moreover, the extinction coefficient K is obtained by the following equation.

  The smoke transmittance measuring device 100 automatically calibrates the absolute value at regular intervals during the measurement, and the measurement light at this time is also converted into an electric signal and then input to the control unit 5. Here, the light transmittance or the extinction coefficient is calculated based on the equations (1) to (3).

And the control part 5 converts the calculated transmittance | permeability into the transmittance | permeability of a desired measurement optical path length as needed. Light transmission T _L after conversion and the light transmittance obtained in the above (1) and T _S is determined by the following equation.

  For example, in the smoke transmittance measuring apparatus 100 of the present embodiment, when the measurement optical path length (short span optical path length) obtained by multiple reflection is 50 [m], and converted to a measurement optical path length of 100 [m] The light transmittance obtained by the above equations 1 and 2 is squared.

Further, the control unit 5 may perform visibility correction so that the obtained light transmittance is adapted to human visibility characteristics. Visibility, which is the sensitivity of the eyes to light, varies depending on the wavelength, and is strongest at a wavelength of 550 [nm]. The relative visibility expressed with reference to 550 [nm] is referred to as specific visibility. FIG. 4B shows a standard relative luminous sensitivity characteristic curve. Further, the wavelength of light projected as measurement light by the light projecting / receiving unit 1 of the present embodiment is 635 [nm], which is illustrated in FIG. 4B. Moreover, the wavelength characteristic of the visibility for each weight concentration [mg / m ³ ] of dust or the like contained in the contaminated air is shown in FIG. 4B.

Here, in order to create a conversion table for correction, the reference for the visibility of human eyes is 550 [nm]. From the graph showing the wavelength characteristic of the visibility when the weight concentration of contaminated air is 0.2 [mg / m ³ ] shown in FIG. ), The visibility is 67.8 [%], and the wavelength of the measurement light (for example, the wavelength of the semiconductor laser) is 635 [nm] (shown by B in the figure). It can be seen that it is 70.1 [%].

Similarly, from the graph showing the wavelength characteristics of the visibility when the weight concentration of the contaminated air is 0.6 [mg / m ³ ], the visibility is 550 nm as the standard of eye sensitivity. It is 34.9 [%], and when the wavelength of the measurement light is 635 [nm], it can be seen that it is 41.1 [%].

Similarly, from the graph showing the wavelength characteristics of the visibility when the weight concentration of the polluted air is 1.0 [mg / m ³ ], the visibility is 550 nm as the eye sensitivity reference. It is 17.8 [%], and when the wavelength of the measurement light is 635 [nm], it can be seen that it is 22.6 [%]. The results are shown in Table 1.

  In this way, a conversion table is created by performing linear interpolation based on the data in Table 1 obtained from the experiment. A conversion table is created in advance and stored in the control unit 5. With this configuration, for example, when the measurement result of the apparatus is 41.1 [%], it can be corrected to 34.9 [%] using the conversion table. As described above, the light transmittance obtained by the measuring apparatus can be corrected to match the human visual sensitivity characteristic, and the light transmittance can be obtained with high accuracy.

  As described above, the haze transmittance measuring apparatus 100 according to the first embodiment multi-reflects the measurement light between the light projecting / receiving unit 1 and the reflection unit 2 of the optical device unit 8 to obtain the desired measurement light. Measurement can be performed with the optical path length. For this reason, it is possible to reduce the size of the measuring cylinder 3 that accommodates the air to be measured. Further, since the volume of the measurement tube 3 is reduced, the time required to store air in the measurement tube can be shortened. For example, the time required to replace the air in the measurement cylinder 3 with the outside air, and the time required to circulate the air in the measurement cylinder 3 at the time of absolute value calibration can be greatly reduced.

  Further, the smoke transmittance measuring apparatus 100 according to the first embodiment can automatically perform 100% absolute value calibration by the absolute value calibration unit 4. Then, by calculating the light transmittance and extinction coefficient by the control unit 5, it is possible to correct the decrease in light transmittance due to the dirt of the glass for optical windows and the variation in light transmittance (temperature drift) due to temperature, so that the measurement accuracy Can be improved.

  Moreover, since the haze transmittance measuring apparatus 100 of this Embodiment 1 calculates | requires the transmittance | permeability of desired measurement optical path length (for example, 100m) by conversion, it reduces the reciprocation frequency between a light projection / reception part and a reflection part, and is based on projection light. The measurement optical path can be shortened by multiple reflection. Therefore, it is possible to suppress a decrease in transmitted light due to scattering by dust-proof glass to which dust / dust adheres and irregular reflection by the reflecting mirror. Even in the case of conversion, since a constant measurement optical path length (for example, about 30 to 60 m) can be ensured by multiple reflection, the influence of error due to conversion can be reduced.

(Embodiment 2)
FIG. 5 shows a schematic configuration of the haze transmittance measuring apparatus 200 according to the second embodiment. In the following description, the same components as those described above are denoted by the same reference numerals, and the description thereof is omitted. As compared with the second embodiment, the present embodiment is characterized in that astigmatism mirrors 20a and 20b are used as reflecting mirrors, as shown in FIG.

  In order to increase the number of reflection points compared to a normal concave mirror (see FIG. 3C, paragraph 0044), an astigmatism mirror can be used as a reflection mirror, thereby reducing the luminous flux of measurement light. By further reducing the internal volume of the measuring tube 3 and reducing the volume of the contaminated air from the outside, the response time to air contamination can be shortened.

(Embodiment 3)
FIG. 6 shows a schematic configuration of the haze transmittance measuring apparatus 300 according to the third embodiment. In the following description, the same components as those described above are denoted by the same reference numerals, and the description thereof is omitted. The feature of the present embodiment is that an embedding material 21 is provided in the measuring tube 3 as shown in FIG.

  With this configuration, the gap between the inner wall of the measuring tube 3 and the luminous flux is eliminated by the embedding material 3, so that the volume of dirty air from the outside can be reduced, thereby shortening the response time to air dirt. can do.

(Embodiment 4)
FIG. 7 shows a schematic configuration of the haze transmittance measuring apparatus 400 of the fourth embodiment. In the following description, the same components as those described above are denoted by the same reference numerals, and the description thereof is omitted. The feature of the present embodiment is that, as shown in FIG. 7, a light receiving cylinder 22 is provided in the pinhole 3b of the reflecting mirror 12a in the light projecting / receiving unit 1, and a light receiving element 23 is provided in the back of the light receiving cylinder 22. It is in.

  With this configuration, the measurement light finally reaching the reflecting mirror 12a through multiple reflections enters the light receiving cylinder 23 through the pinhole 3b, is photoelectrically converted by the light receiving element 23 at the back, and is amplified by the preamplifier circuit 24. Then, it is input to the control unit 5.

  Therefore, the haze transmittance measuring apparatus 400 according to the fourth embodiment can prevent the influence of scattered light due to the dust adhering to the dust-proof glass 11 at the time of receiving light, and can measure the transmittance with high accuracy. Conversion and extinction coefficient can be calculated.

(Embodiment 5)
FIG. 8A shows a schematic configuration of the haze transmittance measuring apparatus 500 of the fifth embodiment. FIG. 8B is a front view of the measuring tube 3 when viewed from the A direction in the drawing. In the following description, the same components as those described above are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIGS. 8A and 8B, the present embodiment is characterized in that a blow-out port 28 is provided in the outer peripheral portion of the dust-proof cylinder 3 in the portion where the dust-proof cylinder 10 is fitted and joined to the measurement cylinder 3. There is in point. The outlets 28 are provided on both the light projecting / receiving unit 1 side and the reflecting unit 2 side.

  The haze transmittance measuring apparatus 500 according to the fifth embodiment includes a clean air generating unit 25 that sends clean air to the outlet 28. The clean air generation unit 25 is connected to the outlet side of the blowout electromagnetic valve 18 of the absolute value calibration unit 4. A clean filter 26 for purifying the air sent from the outlet of the blowout solenoid valve 18 to the clean air generating unit 25, and a clean pump 27 for sending clean air from which dust is removed by the clean filter 26 to the outlet 28 I have.

  With this configuration, the clean air sent out from the clean pump 27 flows out into the measurement tube 3 from the air outlet 28 provided on the outer periphery of the dust-proof tube 10. By this air flow, the contaminated air can be prevented from approaching the dust-proof glasses 11a and 11b provided in the light projecting / receiving unit 1 and the reflecting unit 2, and the dust of the contaminated air can be prevented from adhering to the dust-proof glass.

(Embodiment 6)
FIG. 9 shows a schematic configuration of the haze transmittance measuring apparatus 500 of the sixth embodiment. In the following description, the same components as those described above are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 9, the present embodiment is characterized in that a cleaning port 29 and a cleaning lid 30 that closes the cleaning port are provided in a part of the measurement tube 3, and the dust-proof tube 10 and the dust-proof glass are omitted. There is in point.

  Thus, since the dust-proof cylinder 10 and the dust-proof glass are omitted, the light projecting / receiving unit 1 and the measuring cylinder 3 are directly joined, and the reflecting part 2 and the measuring cylinder 3 are also joined directly. Can be reduced in size. Further, by removing the cleaning lid 30, it is possible to easily and regularly clean the reflector from the cleaning port 29.

  In the above description of the embodiment, the measurement optical path length has been described as 100 [m]. However, the measurement optical path length is not limited to this and may be set to a desired length.

  The haze transmittance measuring device of the present invention is useful as a device for measuring the light transmittance of contaminated air in a tunnel or the like.

Schematic configuration diagram of the haze transmittance measuring apparatus of the first embodiment Schematic configuration diagram of the optical equipment section and absolute value calibration section Front view of reflector Diagram showing reflection point of concave mirror Diagram showing reflection point of astigmatism Diagram explaining how multiple reflections occur The figure which shows the wavelength characteristic of the visibility for every weight concentration of dust etc. which are contained in polluted air Schematic configuration diagram of the haze transmittance measuring apparatus of the second embodiment Schematic configuration diagram of the haze transmittance measuring apparatus of the third embodiment Schematic configuration diagram of the haze transmittance measuring apparatus of the fourth embodiment Schematic configuration diagram of the haze transmittance measuring apparatus of the fifth embodiment Front view when measuring tube is viewed from direction A in FIG. 8A Schematic configuration diagram of the haze transmittance measuring apparatus of the sixth embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitter / receiver 2 Reflector 3 Measuring tube 3a Output point (pinhole)
3b Incident point (pinhole)
DESCRIPTION OF SYMBOLS 4 Absolute value structure part 5 Control part 6 Support metal fitting 7 Base 8 Invar shaft 9 Optical apparatus part 10 Dust-proof cylinder 11a, 11b Dust-proof glass 12a, 12b Reflector 13 Light projection part 14 Light-receiving part 15 Input solenoid valve 16 Calibration solenoid valve 17a , 17b Filter 18 Blowout solenoid valve 19 Suction pump 21 Embedding material 22 Light receiving cylinder 23 Light receiving element 25 Clean air generating part 29 Cleaning port 30 Cleaning lid

Claims (13)

A light projecting / receiving unit that projects and receives light, a reflecting unit that includes a first reflecting mirror that reflects light from the light projecting / receiving unit, and the light projecting / receiving unit and the reflecting unit are associated with each other. A measuring tube provided integrally; and an absolute value calibration means for circulating air in the measuring tube, and the light projecting / receiving unit determines the intensity of light transmitted through the air during normal measurement and absolute value measurement. A haze transmittance measuring device for measuring and measuring light transmittance,
The light projecting / receiving unit has a second reflecting mirror,
The second reflecting mirror is a first pinhole that allows light projected into the measurement tube to pass therethrough, and light that has been multiple-reflected between the second reflecting mirror and the first reflecting mirror. And a second pinhole that allows the light to pass to the light receiving unit.   A shaft that integrally forms the light projecting / receiving portion and the reflecting portion, and a base portion that is fixed by a support bracket at a center of gravity of a central portion of an optical device portion that is integrally formed by the shaft. Item 2. The haze transmittance measuring device according to Item 1.   The haze transmittance measuring device according to claim 1 or 2, wherein the first reflecting mirror and the second reflecting mirror are astigmatism mirrors.   The haze transmittance | permeability apparatus as described in any one of Claim 1 to 3 with which the embedding material is formed in the inner wall of the said measurement cylinder. The light projecting / receiving unit and the measuring cylinder are joined via a dust-proof cylinder,
The dust-proof cylinder has dust-proof glass,
5. Any one of claims 1 to 4, wherein a light receiving cylinder is provided on a light projecting / receiving part side of a second pinhole formed in the second reflecting mirror, and a light receiving element is provided inside or at an exit portion of the light receiving cylinder. The haze transmittance measuring device according to claim 1. The light projecting / receiving unit and the measuring cylinder are joined via a dust-proof cylinder,
The dust-proof cylinder has dust-proof glass,
The measurement tube has a blowout port near the outer periphery surrounding the dust-proof tube,
The haze transmittance measuring device according to any one of claims 1 to 5, further comprising a clean air generating unit that sends clean air to the outlet. The reflection part and the measurement tube are joined via a dust-proof tube,
The dust-proof cylinder has dust-proof glass,
The measurement tube has a blowout port near the outer periphery surrounding the dust-proof tube,
The haze transmittance measuring device according to any one of claims 1 to 5, further comprising a clean air generating unit that sends clean air to the outlet.   The said dust-proof glass is a haze transmittance | permeability measuring apparatus as described in any one of Claim 5 to 7 provided in the cylinder inside of the said dust-proof cylinder.   The said measurement cylinder is a haze transmittance | permeability measuring apparatus as described in any one of Claim 1 to 5 which has an opening-closing part.   The said absolute value calibration means is a hose transmittance | permeability measuring apparatus as described in any one of Claim 1 to 9 which is a hose which the hose which distribute | circulates air is hard to be charged.   The haze transmittance measuring apparatus according to any one of claims 1 to 10, further comprising a calculation unit that converts the transmittance obtained from the measured optical path length of the multiple reflected light into the desired measured optical path length.   The said transmittance | permeability measurement apparatus as described in any one of Claim 1 to 11 which performs the visibility correction | amendment which adapts a transmittance | permeability to a human visual sensitivity characteristic.   The calculation means is an absolute measurement value after the set time has elapsed from the start of absolute value calibration and when the measured value of the transmittance has converged within the set range. The haze transmittance measuring device according to any one of claims 1 to 12.

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